Linear motion systems for industrial machinery and tooling often employ ball or acme screws driven by a servo motor to facilitate linear motion. The typical arrangement in these systems is that a stationary rotary motor drives a threaded screw that impart rectilinear motion upon a movable carriage that has a threaded nut engaging the screw. The movable carriage is then typically guided by a linear motion system such as one of those systems commercially available from the present assignee, Pacific Bearing Company®, located in Rockford, Ill.
However, there is another type of linear motor which uses magnetic propulsion that is sometimes referred to as a thrust tube motor or a thrust tube module (both of which are referred to herein generically as “motor”). Such thrust tube motors are set forth in literature entitled “ThrustTube Motors” and “ThrustTube Modules” and are sold under different products models commercially available from Copley Controls Corp., located in Canton, Mass. As is generally disclosed thereby, prior thrust tube motors include a thrust tube and a thrust block that linearly reciprocates relative to the thrust tube. The thrust tube typically includes a linear array of permanent magnets (e.g. many linearly stacked magnets providing multiple north and south poles) surrounded by electrical coils mounted centrally in a thrust block, that when energized drives the thrust block carriage relative to the thrust tube. To control the energizing of the electrical coils, a motor controller is typically provided at a stationary remote position from the thrust block carriage. The motor controller is connected via wiring through a flexible conduit that allows for movement of the thrust-block carriage. As also disclosed thereby, these systems are often associated with separate linear bearing motion systems.
Heretofore, there have been too many deficiencies with thrust tube motors to allow them to effectively compete or provide a commercially practical alternative to screw type servo motors. These prior systems are often too complex, require too many components, have undesirable mounting requirements and are too expensive to effectively compete in the marketplace for many machine applications, despite several technological advantages that thrust tube motors or modules provide over screw type servo motors.